Therapeutic compositions comprising 6-fluoro-16-methyl prednisolone, the 21 acylates and salts thereof

ABSTRACT

This invention relates to therapeutic compositions and more particularly to therapeutic compositions comprising a 6 Alpha fluoro-11 Beta ,17 Alpha ,21-trihydroxy, 16 Alpha -methyl-1,4pregnadiene-3,20-dione and 21-acylates and water-soluble salts thereof as an essential active ingredient in combination with a pharmaceutical vehicle.

United States Patent Frank H. Lincoln Kalamazoo;

William P. Schneider, Kalamazoo Township, Kalamazoo County; George B. Spero, Kalamazoo, all of Mich.

Aug. 1 l, 1959 Dec. 7, 1971 Upjohn Company Kalamazoo, Mich.

Continuation-in-part of application Ser. No. 753,157, Aug. 4, 1958, now Patent No. 3,499,016. This application Aug. 11, 1959, Ser. No. 832,898

The portion of the term of the patent subsequent to Mar. 3, 1987, has been disclaimer].

[72] Inventors [2]] Appl. No. [22] Filed [45] Patented [73] Assignee [54] THERAPEUTIC COMPOSITIONS COMPRISING 6- FLUORO-ltS-METHYL PREDNISOLONE, THE 21 ACYLATES AND SALTS THEREOF 8 Claims, No Drawings [52] U.S.Cl 424/243,

[51] Int. Cl C07c 169/32 [50] Field of Search 167/77, 651 N [56] References Citedl UNITED STATES PATENTS 3,499,016 3/1970 Lincoln et a1 260/2395 2,838,542 6/1958 Spero et al 167/77 X 2,838,543 6/1958 Spero et a1 167/77 X 2,841,600 7/1958 Hogg et al 167/77 X Primary Examiner-Elbert L. Roberts Anurneys- Eugene O. Retter and Joseph K. Andonian ABSTRACT: This invention relates to therapeutic compositions and more particularly to therapeutic compositions comprising a 6a-fluoro-llB,l7a,2l-trihyd1roxy, l6a-methyl-l,4- pregnadiene-3,20-dione and 2l-acylates and water-soluble salts thereof as an essential active ingredient in combination with a pharmaceutical vehicle.

THERAPEUTIC COMPOSITIONS COMPRISING 6- bon atoms, inclusive, or water-soluble salts of a pharmacologi- FLUOR0-l6-METHYL PREDNISOLONE, THE 2! cally acceptable anion and an acid ester of a dicarboxylic acid ACYLA'IES AND SALTS THEREOF containing from four to l6 carbon atoms. inclusive. the said This application is a continuation-in-part of application Ser. principal active ingredients either singly or in combination. No. 753,!57, filed Aug. 4. l958nowPaL No. 3,499,016. 5 being dispersed in a pharmaceutical carrier.

The novel compositions of the present invention comprise The compositions of the present invention are uscthl in the as the principal active ingredient, a compound of the formula: treatment of humans and animals for various pathological conditions. The compositions provide a means for administration of the therapeutic ingredient by the oral and parenteral H30 0:0 10 routes for systemic treatment as well as topical or localized L-- treatment. The invention provides a method for the treatment H0 of conditions such as rheumatoid arthritis, rheumatic fever, H, various dermatoses, eye and ear inflammations, joint (intraargC ticular) inflammatlon and adrenal hyperplasia. The composil5 tions are advantageous for treating said conditions for reason of the improved ration of therapeutic activity to undesirable 0 side-effects, e.g., gastrointestinal disturbances, salt retention, v edema, etc., known to exist with similar lknown therapeutically '4 active steroids.

20 The following diagrams and description illustrate the wherein R is hydroxy, acyloxy, in which the acyl radical is that preparation of the therapeutic ingredient of the compositions of an organic carboxylic acid containing from one to carof the present invention:

The preceding diagrams X, X, X", and X' represent the forms of the therapeutic ingredient of the compositions of the present invention. The said form can be named as derivatives of prednisolone, such as, for example, 6a-fluoro-l6a-methylprednisolone, 6a-fluorol 6a-methylprednisolone 2 l acetate, 6a-fluoro-l6a-methylprednisolone (2i) hemisuccinate, and 6a-fluorola-methylprednisolone (21 succinate sodium.

The starting 3,1 l-diketol 6a-methyl-4, l 7(20)-pregadien- 2 l-oic acid methyl ester is prepared from the known ll-ketolo-dehydroprogesterone by the following reactions: The 3- keto group of l l-keto-lG-dehydroprogesterone is selectively protected from reaction by conversion to a 3-enamine, e.g., pyrrolidyl enamine, according to procedures well-known in the art. The 3-enamine of l l-keto-l6-dehydroprogesterone is .then reacted with a methyl Grignard reagent, preferably methyl magnesium bromide or iodide, in the presence of a l ,4- addition promoting reagent, e.g., cuprous chloride, [See Grignard Reactions," Kharasch and Reinmuth, Prentice Hall, lnc. Publishers (1954), page 219, for a discussion of other catalysts], to produce the 3-enamine of l l-keto-l6a-methylprogesterone, The 3-enamine group is then hydrolyzed, e.g., with aqueous alkali to produce ll-keto-l6a-methylprogesterone. The 3-enamine group is then hydrolyzed, e.g., with aqueous alkali to produce 1 l-ket0-l6a-methylprogesterone.

l l-keto-la-methylprogesterone is then converted to 3,l ldiketol 6a-methyl-4, l 7( 20)-pregnadien-2 l -oic acid loweralkyl ester (l) in the manner described in U.S. Pat. No. 2,790,814 for the conversion of l lketoprogesterone to 3,1 ldiketo-4,l7( 20)-pregnadien-2l-oic acid methyl ester, i.e., l lketo-l6a-methylprogesterone is reacted with more than two molar equivalents each of an alkyl diester of oxalic acid, preferably methyl or ethyl oxalate, and a base, preferably sodium methoxide or ethoxide or potassium tertiary butoxide, to produce the alkali-metal dienolate of 2,2 l-dialkoxyoxalyl-l lketo-l6a-methylprogesterone. This compound, or the free enol, e.g., prepared by reaction of the alkali-metal dienolate with acetic acid, is then trihalogenated with chlorine or bromine, preferably the latter, to produce 2,2ldialkoxyoxaalyl-2,2l,2l-trihalol l-keto-l6a-methylprogesterone. This compound rearranges with strong base, e.g., an alkali-metal alkoxide, in the presence of an alkanol, e.g., sodium methoxide or ethoxide in methanol or ethanol, to produce 2-halo- 3,l l-diketo-l6a-methyl-4, l 7(20)-pregandien-2 l -ic acid alkyl ester. The 2-halo group is removed by zinc and acetic acid or other halogen removing agent to produce 3,l l-diketol6a-methyl-4,l 7(20)pregandien-2 l -oic acid alkyl ester (l).

The therapeutic ingredient of the present invention is prepared from 3,l l-diketo-l6a-methyl-4,l7(20)-pregandien- 2l-oic acid lower-alkyl ester (1) by the following reactions: The 3-keto group is ketalized according to the method of U.S. Pat. No. 2,707,184 or 2,758,993 to produce the 3-ketal of 3, l l-diketo-l6a-methyl-4,17(20)-pregandien-2l-oic acid lower-alkyl ester (ll). Ethylene glycol is the preferred ketalizing agent and the methyl and ethyl esters are preferred.

The next step of the process involves the epoxidation of the (6)-double bond of a 3-ketal of 3,1l-diketo-l6a-methyl- 4,l7(20)-pregandien-2l-oic acid lower-alkyl ester with a peracid, e.g., peracetic or perbenzoic, or other known epoxidizing agents, to produce the corresponding 5,6-epoxide (III). A mixture of both the aand B-epoxides is produced in this epoxidation reaction, the mixture can be separated by chromatographic or crystallization techniques known in the art. The a-epoxide is employed in the next step.

The next step is an epoxide opening step in which a 3-ketalized 3,l l-diketo-Sa, 6a-epoxyl 6a-methyll 7( 20)-pregnen- 2l-oic acid lower-alkyl ester (III), is reacted with hydrogen fluoride, to open the oxide ring and produce the correspondin g 3-ketalized 3 ,l l-diketo-5a-hydroxy-QB-fluorol 6amethyl-l7(20)-pregnen-2l-oic acid lower-alkyl ester (V). This epoxide opening step is ordinarily carried out at temperatures between about minus 40 and plus 50' centigrade, the preferred limits being between about 0 and 25 centigrade. It can be performed under anhydrous conditions in the presence or absence of a catalyst, e.g., boron trifluoride, or under aqueous conditions in which case the ketal group is removed by hydrolysis. Reaction conditions, e.g., those disclosed by Schmidlin et al., Helv. Chim. Acta, 36, 124] (1953): Gallagher, J. Biol. Chem., 162, 495 (1946); Cornforth et al., J. Chem. Soc., 1954, 907 and Fried et al., J. Am. Chem. Soc., 75, 2273 (1953), are usually employed. As anhydrous conditions are often difficult or inconvenient to maintain, the oxide opening reaction is preferably performed under aqueous conditions in which case the ketal group will by hydrolyzed at the same time to produce IV. The thus-produced 3-keto group of N can then be reketalized in the manner described hereinabove to produce the corresponding ketal (V).

The next step of the process is a reduction step in which a 3- ketalized 3-keto-5a-hydroxy-fi-fluorol 6a-methyll 7( 20)- pregnan-Zl-oic acid lower-alkyl ester (v), preferably the 3- ethylene glycol ketal of 3,1 1-diketo-5u-hydroxy-fiB-fluoro-16 a-methyl-l7(20)-pregnan-2l-oic acid lower-alkyl, preferably methyl or ethyl, ester, is reduced with lithium aluminum hydride or other chemical carboxyl reducing agent in an organic solvent, e.g., ether, dioxane, tetrahydrofuran, benzene, to produce the corresponding 3-ketalized 5a, 1 1,6, 21- trihydroxy-fiB-fluorol Ga-methyll 7( 20)-pregnen-3-one. At completion of this reaction, the reaction mixture is preferably mixed with water or, an acid, an ester of carbonyl agent followed by water, to decompose an excess lithium aluminum hydride and organometal complexes. The usual reaction conditions for a lithium aluminum hydride reduction are employed, except that a reaction temperature at room temperature or below is preferred, and acid, though operative and satisfactory under carefully controlled conditions, is preferably not employed in the decomposition step, to avoid undue hydrolysis of the ketal group.

The next step is an esterification reaction involving the conversion of the 2l-hydroxy group of a 3-ketal of 5a, 1 1B, 21- trihydroxy-ofi-fluorol 6a-methyll 7(20)-pregnen-3-one (Vl) to a 2l-acyloxy group so as to protect the 2 1 -hydroxy group in the next step, i.e., the oxidative hydrloxylation stepv This reaction can be performed under the esterification conditions known in the art, e.g., by the reaction of IV with the selected acid halide, e.g., acid chloride or acid bromide, or the anhydride of a hydrocarbon carboxylic acid, or by reaction with the selected acid, in the presence of an esterification catalyst or with an ester under ester exchange reaction conditions. Reaction conditions which are apt to affect the labile 3-ketal group, the l lB-hydroxy group or the 6-fluoro group should be avoided.

In the next step of the process, the thus-produced ester (Vll) is then oxidatively hydroxylated with osmium tetroxide and an oxidizing reagent, e.g., hydrogen peroxide, organic peracid, an amine oxide peroxide, or an aryl iodo oxide, in the manner described in US. Pats. No. 2,769,825, 2,769,823 or in Hogg et al., J. Am. Chem. Soc., 77, 4436 (1955), to produce the corresponding 3-ketal of 5a, 111B, 170:, ZI-tetrahydroxy- 6B-fluoro-l6a-methylpregnane-3,20-dione 2 l -acylate (VIII).

The next step of the process involves the simultaneous removal of the 3-ketal group, the dehydration of the 50:- hydroxy group and the epimeriztion of the GB-fluoro group of a 3-ketal of 5a, 113, 17a, 2l-tetrahydroxy-fiB-fluoro-16amethylpregnane-3,20-dione 2l-acylatte to produce (nu-fluoro- 1 [BI 2 l -trihydroxyl 6a-methyl-4-pregnene-3 ,20-dione 2l-acylate (IX). Although these reactions can be performed in sequence, i.e., removal of the 3-ketal under mildly acidic conditions, the dehydration using Girards Reagent T and the epimerization using anhydrous mineral acid, these reactions are preferably performed simultaneously. This can be accomplished under acidic conditions, preferably employing a mineral acid in an inert solvent for the steroid, e.g., chloroform or methylene chloride, and preferably in the presence of a lower alkanol, e.g., methanol or ethanol.

The a-fluoro-l 15, 17a, 2l-trihydroxy-16a-methyl-4- pregnene-3,20-dione 2l-acylate (IX) thus produced can be hydrolyzed to the corresponding free 2l-alcohol (lX) in accordance with known methods for hydrolyzing Compound F 2l-esters to the free Compound I? alcohol. A preferred procedure is to employ at least a molar equivalent of an alkali metal bicarbonate, e.g., potassium bicarbonate; in a substantially oxygen-free solution of a mixture of lower alkanol and water. The hydrolysis reaction is carried out at a temperature between 10 and 70 centigrade while protecting the mixture from atmospheric oxygen. After the hydrolysis is complete, the reaction mixture is neutralized with n acid, e.g., acetic acid, and the hydrolyzed product (lX) recovered from the reaction mixture by evaporation and crystallization, extraction with methylene chloride and the like.

The 6a-fluoro-l 1B, ZI-trihydroxy-l6a-methyl-4- pregnene-3,20-dione (lX) or its 21-:acylate (IX), preferably the 2 l -acetate, can be converted to the therapeutic ingredient of the composition of the present invention. For example, they (IX and IX) can be dehydrogenated at the one position with selenium dioxide or a fungus capable of dehydrogenating at the one position without otherwise degrading the nucleus, e. g., of the genus. Septomyxa, to produce a-fluoro-l ll l7a, 2ltrihydroxyl 6a-methyl-l ,4-pregnadiene-3,20-dione (X). This compound, in turn, can be esterified to produce its 2l esters (X) by reaction with the appropriate acid anhydride, acid chloride or bromide, or by other methods known in the art. Alternatively, the fia-fluoro-l 13, 17a, 2l-trihydroxy-l6amethyl-l ,4-pregnadiene-3,20-dione (X) is reacted with an excess of carboxylic inner anhydride of a dibasic acid, e.g., succinic, glutaric, a-mcthylglutaric, fl-methylglutaric, ,8, B- dimethylglutaric, adipic, pimelic, suberic, and the like, in a mutual solvent, advantageously, an organic base such as pyridine or lutidine. The reaction normally takes place within a few hours at room temperature. Gentle heating can be used, but is generally undesirable. Also if the anhydride is sufficiently active or if a longer time is used, temperatures below room temperature are used.

The product hemiester (X") can be recovered from the reaction mixture by the usual procedures. Advantageously the mum product is precipitated by adding a liquid which is capable of precipitating the product as the free acid ester or a salt thereof. An aqueous solution of hydrochloric acid or like strong mineral acid can be used advantageously when pyridine or like organic base is used as the mutual solvent. Ordinarily it will be sufficient to pour the reaction mixture slowly into an excess of dilute aqueous hydrochloric acid and then filter off the precipitated product. The product can be further purified by crystallization from apolar solvent such a acetone. Suitable other solvents include: methyl ethyl ketone, methanol, ethanol, isopropanol, B-ethoxyethanol, ethyl acetate and mixtures of the same with Skellysolve B, ether and water where the resulting solvent system is homogeneous.

The free acid hemiester thus produced can be converted to a salt by neutralization with the appropriate base. Advantageously the free acid hemiester can be dissolved in a volatile water-miscible solvent, such as acetone, and the solution neutralized by adding aqueous alkali or alcoholic alkali. Advantageously the pH is adjusted to from about 7.2 to about 7.4. Other volatile water-miscible solvents include: methanol, ethanol, isopropanol and dioxane. The solvent is then removed by vacuum distillation, first the volatile solvent and then the water. Advantageously the water is removed by lyophilization. Before lyophilization the water solution can be filter sterilized if a sterile produce is desired. Suitable bases are the alkali and alkaline earth metal hydroxides and carbonates, such as sodium, potassium, ammonium, calcium and magnesium hydroxides and carbonates and lower molecular weight ammonium bases.

The following preparations are illustrative of the preparation of the therapeutic ingredients of the invention, but are not intended to be limiting.

Preparation I l 1 -keto- 1 6a-methylprogesterone To a hot solution of 4.56 grams (0.014 mole) of 1 1-keto-16- dehydroprogesterone in 45 milliliters of methanol was added 2.25 milliliters of pyrrolidine with swirling. The reaction product, the 3-pyrrolidyl enamine of l l-keto-l6- dehydroprogesterone, soon separated as yellowish crystals. After cooling to 5, the mixture was filtered, the cake washed with cold methanol and dried under vacuum. There was obtained 4.56 grams of 3pyrro1idyl-3,5,16-pregnatriene-1 1-20- dione melting at 154 to 169 centigrade.

A solution of the thus-obtained enamine in 1 milliliters of tetrahydrofuran was added slowly to a stirred suspension of 45 milliliters of commercial three molar methyl magnesium bromide, 0.90 gram of cuprous chloride and fifty milliliters of tetrahydrofuran. The mixture was cooled to room temperature and stirred under a nitrogen atmosphere for 3 hours. The excess Grignard reagent was cautiously destroyed by the dropwise addition of 29 milliliters of water. To the mixture, containing 3-pyrrolidyll 6a-methyl-3 ,S-pregnadiene-l 1,20- dione, was added 18 milliliters of acetic acid and 72 milliliters of methanol and the mixture was warmed until a clear dark yellow solution was obtained. One hundred three milliliters of a 10 percent aqueous solution of sodium hydroxide was added, bringing the pH to 8. The mixture was heated under reflux for 45 minutes. 5 milliliters of acetic acid and 250 milliliters of water were added and the cooled mixture was extracted three times with methylene chloride. The combined extracts were washed with an aqueous sodium bicarbonate solution, water and then dried with sodium sulfate. The dried solution was evaporated and the residue, consisting essentially of 1 l-ketol fiat-methylprogesterone, was dissolved in 400 milliliters of methylene chloride and chromatographed through a 200 gram column of magnesium silicate (Florisil). The column was developed with 400 milliliter portions of solvent of the following composition and order: five of hexanes (Skellysolve B) plus 3 percent acetone, five of hexanes plus 5 percent acetone, eight of hexanes plus 7 percent acetone, five of hexanes plus 10 percent acetone, four of hexanes plus percent acetone and finally, one of acetone. Fractions nine to 25 (counting the methylene chloride fraction) were combined and recrystallized from a mixture of acetone and water to give 2.03 grams of 1 l-keto-loo-methylprogesterone melting at 179 to 182 centigrade. A sample recrystallized from a mixture of ethyl acetate and hexanes melted at 183 to 185 centigrade, had an [11],, of plus 255 (CHCl A 238 ;4.,a 15,850 and the analysis below.

Calculated for C fl o z C, 77,15; H, 11.83.

Found: C, 76.95; H, 8.98.

PREPARATION 2 3,1 1-diketo-l6a-methy1-4,l7(20)-pregnadien-21-oic methyl ester A solution of 2.00 grams (5.8 millimoles) of l 1-keto-l6amethylprogesterone in 30 milliliters of dry tertiary butyl alcohol was warmed to 50 centigrade and stirred under nitrogen. To the solution was added 3.2 milliliters of ethyl oxalate and 3.03 grams of a 25 percent methanolic sodium methoxide solution. A yellow-green precipitate of the sodium dienolate of 2,2 l -diethoxyoxalyl-l l-keto- 1 6a-methylprogesterone appeared almost immediately.

The mixture was stirred for 20 minutes after which a cooled solution of 0.98 gram of anhydrous sodium acetate and 0.84 milliliter of acetic acid in 40 milliliters of methanol was added, thus producing the free dienol. The solution was cooled to 0 C. and then treated dropwise with a cold solution of 2.0 grams of bromine in methanol over a period of 10 minutes. There was thus-produced 2,21,2l-tribromo-2,2l-diethoxyoxalyl-l lketo-16a-methylprogesterone.

The cooling bath was removed and to the solution was added 5.72 grams of a 25 percent methanolic sodium methoxide solution. The stirring was continued for 2.5 hours. There was thus produced 2-bromo-3,1 1-diketo-16a-methyl-4,17(20 )-pregnadien-2 l-oic acid methyl ester.

To the resulting solution was then added 5 milliliters of acetic acid and 1 gram of zinc dust and stirring was continued for 30 minutes. The mixture was diluted with water, the solids were removed by filtration, and the filtrate extracted thoroughly with methylene chloride. The extract was dried with sodium sulfate and evaporated. The residue was dissolved in 400 milliliters of methylene chloride and poured over a 200 gram column of magnesium silicate (F lorisil). The column was developed with 400 milliliter portions of solvent of the following composition and order: four of hexanes (Skellysolve B) plus 5 percent acetone, ten of hexanes plus 7 percent acetone, ten of hexanes plus 10 percent acetone and finally, one of acetone. Fractions 14 to 23 (counting the methylene chloride fraction) contained starting 1 l-keto-l6a-methylprogesterone. Fraction 7 to 12 contained 3,1 1-diketo-l6a-methy1-4, 1 7(20)- pregnadien-21-oic acid methyl ester which, when crystallized from methanol and water and then from methanol, melted at 177 to 184 centigrade, has a A $532325 1., a 26.200, an [01],, of plus 137 (CHCl and the analysis below.

acid

Calculated for C H O C, 74.56; H. 8.16.

Found: C, 74.58; H, 11.04.

The yield of product is increased if the initial reaction of 1 1- keto-l(Ea-methylprogesterone with ethyl oxalate and sodium methoxide is conducted at somewhat higher temperatures and/or with longer reaction times.

PREPARATION 3 The 3-ethylene glycol ketal of 3,11-diketo-l6a-methyl- 4,17(20)-pregnadien-2l-oic acid methyl ester To a solution of 1.5 grams of 3,11-diketo-l6a-methyl- 4,17(20)-pregnadien-21-oic acid methyl ester dissolved in milliliters of benzene was added 7.5 milliliters of ethylene glycol and 0.150 gram of paratoluenesulfonic acid and the whole was then heated with stirring at the reflux temperature of the reaction mixture for 5.5 hours. The water formed in the reaction was removed by passing the condensate through a water trap. The cooled reaction mixture was washed with 100 milliliters of a 1 percent aqueous sodium bicarbonate solution. The benzene layer was then poured on a column of 150 grams of magnesium silicate (Florisil). The column was developed with 100 milliliter portions of solvent of the following composition and order: eight portions of methylene chloride plus 4 percent acetone and three portions of methylene chloride plus 8 percent acetone. The methylene chloride plus 4 percent acetone eluates contained the 3-ethylene glycol ketal of 3,1 1- diketo-l6a-methyl4,17(20)- pregnadien-Zl-oic acid methyl ester which was freed of solvent by evaporation.

Reacting 3,1 l-diketol 6a-methyl-4, l 7( 20)-pregnadien-2 1 oic ucltl methyl ester with trimethylene glycol in the presence of pnrululuencuulfonic acid is productive of the 3- trimcthylcne glycol ketal of 3,1 l-diketo-l6a-methyl- 4,17(2())-pregnadien-2l-oic acid methyl ester.

Similarly, other 3-ketals of this and other esters of 3,11- diketo-l 6a-methyl-4, l 7( 20)-pregnadien-2 l -oic acid methyl ester.

Similarly, other 3-ketals of this and other esters of 3,11- diketo-l 6a-methyl-4,17(20)-pregnadien-2l-oic acid methyl ester are produced by the reaction of the selected ester of 3,1 l-diketo-l6a-methyl-4,17(20)-pregnadien-2l-oic acid, e.g., methyl, ethyl, propyl, butyl, or octyl ester, with a glycol as hereinbefore described, e.g., ethylene glycol, propylene glycol, trimethylene glycol, lower-alkyl substituted ethylene glycols or trimethylene glycols, in the presence of an acid catalyst, e.g., toluenesulfonic acid, hydrogen chloride, sulfuric acid.

PREPARATION 4 3-ethylene glycol ketal of 3,1 l-diketo-Sa, 6a-epoxy-l6amethyl-17(20)-pregnene-2l-oic acid methyl ester To a solution of 5 grams of the 3-ethylene glycol ketal of 3,1 1-diketo-l6a-methyl-4,17(20)-pregnadien-2l-oic acid methyl ester in 100 milliliters of chloroform was added a chilled solution of 1.9 grams of perbenzoic acid dissolved in 31.5 milliliters of chloroform. The solution was maintained at about four centigrade for 24 hours, and then at room temperature for 72 hours. The solution was then washed with a 5 percent aqueous solution of sodium bicarbonate and then with water. The chlorofonn layer was separated, dried and the solvent distilled to give a residue of the 3-ethylene glycol ketal of 3 ,l 1-diketo-5a6a-epoxy-16a-methyl-17(20)-pregnen-2l-oic acid methyl ester.

PREPARATION 5 3 ,1 1-diketo-Sa-hydroxy-6B-fluoro-16a-methyl-l7(20)- pregnen-2 l-oic acid methyl ester To a solution of 1.73 grams of 3-ethylene glycol ketal of 3,1 1 -diketo-5a, 6u-epoxyl oa-methyl- 1 7(20)-pregnen-2 l-oic acid methyl ester in 16 milliliters of methylene chloride was added 6 milliliters of 48 percent hydrofluoric acid. The heterogeneous mixture was stirred for 2 hours, made slightly basic with 200 milliliters of 5 percent sodium bicarbonate solution, and extracted with methylene chloride. The extract was washed, dried, and evaporated to dryness to give 1.62 grams of crude solid. Purification by chromatography over magnesium silicate gave two fractions. The first was eluted with methylene chloride plus 5 percent acetone and the second was eluted with methylene chloride plus and 20 percent acetone. Crystallization of the first fraction from a mixture of acetone and Skellysolve B hexanes gave 3,11- diketo-5a-hydroxy-6B-fluorol 6a-methyll 7( 20)-pregnen- 2 l -oic acid methyl ester.

PREPARATlON 6 3-ethylene glycol ketal of 3,1 1-diketo-5a-hydroxy-6B-fluorol6a-methyl-l 7(20)-pregnen-21-oic acid methyl ester A mixture of 1.9 grams of 6/3-fluoro-3,1 l-diketo-5ahydroxyl 6a-methyl- 1 7( 20)-pregnen-2 l-oate, 59 milligrams of paratoluenesulfonic acid monohydrate and 31 milliliters of distilled ethylene glycol was added to 800 milliliters of benzene. The mixture was stirred and refluxed for 2 hours, with the condensate passing through a water trap to remove the water. Then the mixture was cooled, washed with water and evaporated to dryness to give a crude solid which on recrystallization from a mixture of acetone and hexanes gave the 3-ethylene glycol ketal of 3,1 1-diketo-5a-hydroxy-6B- fluoro-16a-methyl-l 7(20)-pregnen-2 loic acid methyl ester.

Following the above procedure, substituting other dihydric alcohols for ethylene glycol, for example, l,2-propylene glycol, 2,3-butanediol, 1,3-butanediol and 2,3-pentanediol, is productive of the respective 3-alkylene ketals of 3,1 l-diketo- 5a-hydroxy-6fi-fluoro-l6a-methyl-l7ll20)-pregnen-21-oic acid methyl ester. PREPARATION 7 The 3-ethylene glycol ketal of 5a, 113, 2l-trihydroxy-6,B- fluoro-16a-methyl-l7(20)-pregnen-3'one To a solution of 1.96 grams of the 3-ethylene glycol ketal of 3,1 l-diketo-Sa-hydroxy-6B-fluoro-16a-methyl-l7(20)- pregnen-Zl-oic acid methyl ester in 850 milliliters of anhydrous ether was added 3.7 grams of lithium aluminum hydride. The mixture was stirred for a period of 1 hour, and 200 milliliters of water was added slowly, the ether phase separating. The aqueous phase was extracted with ethyl acetate and the extracts added to the ether phase. The combined ether-ethyl acetate solution was washed with water, dried and evaporated to dryness under reduced pressure. The crude solid residue was crystallized from acetone-Skellysolve B hexanes to give the 3-ethylene glycol ketal of 5a, 1 1,8, 2 ltrihydroxy-6B-fluoro-1Sa-methyl-l 7(20)-pregnen-3-one.

PREPARATION 8 The 3-ethylene glycol ketal of 5a, 1 1,8, 2l-trihydroxy-6B- fluoro-16a-methy1-17(20)-pregnen-3-one 2 [-acetate 0.87 gram of the 3-ethylene ketal of 5a, 1 1B, 2 l -trihydroxy- 6B-fluoro-16a-methyl-l7(20)-pregnen-3-one was dissolved in 10 milliliters of acetic anhydride and ten milliliters of pyridine. The solution was maintained 16 hours at room temperature and then poured into ice water to give the 3ethylene glycol ketal of 5a, 1 113,21-trihydroxy-6B-fluoro-l6a-methy1-17(20)- pregnen-B-one 2 l -acetate.

Similarly, other 2l-organic carboxylic acid esters of 5a, 1 1B, 21-trihydroxy-6B-fluoro-l6a-methyl-17(20)-pregnen-3- one 3-ethylene ketals can be prepared wherein the 21-acyloxy group is formyloxy, propionyloxy, butyryloxy, valeryloxy, hexanoyloxy, heptanoyloxy, octanoyloxy, benzoyloxy, phenylacetoxy, or the like, by contacting the 3-ethylene ketal of 5a, 1 1B, 21-trihydroxy-6B-fluoro-16a-methyl-17(20)- pregnen-3-one with the appropriate acylating agent, e.g., the anhydride or acid halide of the selected acid in a solvent such as benzene, toluene, acetic acid, or the like, preferably in the presence of pyridine or a similar amine.

PREPARATION 9 The 3-ethylene glycol ketal of 5a, 1 1B, 2l-tetrahydroxy 6B-fluorol 6a-methylpregnane-3 ,ZO-dione 2 l -acetate To a solution of 0.93 gram of the 3-ethylene glycol ketal of 501, l l,B-dihydroxy-6,B-fluoro-l6a-methyl-l 7(20)-pregnen-3- one 2l-acetate in 35 milliliters of tertiary butyl alcohol was added 1 milliliter of pyridine, 2.75 milliliters of two molar N- methylmorpholine oxide peroxide (U.S. Pat. No. 2,769,823) in tertiary butyl alcohol, and 13.1 milligrams of osmium tetroxide in tertiary butyl alcohol (9.] milliliters of tertiary butyl alcohol solution containing 1.44 milligrams osmium tetroxide per milliliter). The solution was stirred for a period of 18 hours and 15 milliliters of 5 percent sodium hydrosulfite was added. Stirring was continued for an additional 10 minutes, at which time 0.7 gram of linely ground synthetic magnesium silicate was mixed into the solution for a period of 20 minutes and then removed by filtration. The filtrate was PREPARATION l fia-fluoro-l 1,8, 170:, 2 l-trihydroxyl 6a-methyl-4-pregnene- 3,20-dione 2 1 -acetate A solution of 0.144 gram of the 3-ethylene glycol ketal of 5a, 113, 17a, 2l-tetrahydroxy-GB-fiuoro-l6a-rnethyl pregnane-3,20-dione 2 l-acetate in 12 milliliters of chloroform and 0.1 milliliter of absolute alcohol was cooled to minus centigrade in an ice-salt bath and a stream of anhydrous hydrochloric acid was gently bubbled through the solution for 2.5 hours while the temperature was maintained between minus 5 and minus 15 centigrade. The solution was then diluted with 25 milliliters of chloroform, washed with dilute sodium bicarbonate and water, dried over anhydrous sodium sulfate, and evaporated to dryness under reduced pressure at 60 centigrade or less to give a-fiuoro-l 1,3, 17a, 21- trihydroxyl 6a-methyl-4-pregnene-3,20-dione 2 l -acetate.

PREPARATION l l 6a-fluorol 13, 17a, 2 l-trihydroxyl 6a-methyl-4-pregnene- 3,20dione A solution of 1.1 grams of 6a-fluoro-l 13, 17a, 21- trihydroxyl 6a-methyl-4-pregnene-3,20-dione 2 l-acetate, l g. of potassium bicarbonate, 100 ml. of methanol and 15 ml. of water were mixed together and purged with nitrogen to remove dissolved oxygen while stirring at 25 C., for 4 hours. The solution was then neutralized by addition of acetic acid and distilled under vacuum to remove the methanol. The residue was extracted with 100 ml. of methylene chloride, and the extract was dried over sodium sulfate to give a solution of 6a-fluoro-l 113, I70, 2 l-trihydroxyl 6amethyl-4-pregnene- 3,20-dione which was freed of solvent by evaporation.

PREPARATION l2 6a-fluoro-l 113, 17a, pregnadiene-3,20-dione A medium consisting of 1 percent dextrose hydrate, 2 percent cornsteep liquor of 60 percent solids and tap water was adjusted to pH 4.9 with sodium hydroxide. The medium was steam sterilized at 15 pounds pressure for 30 minutes, cooled, and then inoculated with a 24 hours growth, from spores, of Seplomyxa affinis, A.T.C.C. 6737. The medium was agitated, and sparged with sterile air at the rate of one-tenth volume of air per volume of medium per minute. At the end of 24 hours of fermentation at room temperature, the pH was about 7.4. To this culture there was added a solution of oa-fluoro-l 13, 17a, 2 l-trihydroxyl 6a-methyl-4-pregnene-3,20-dione 2 l acetate dissolved in a minimal amount of diethylformamide. The solution was prepared by dissolving five parts of the steroid in 100 parts of the solvent and adding about 10 cc. of the solution per liter of the medium. Fermentation was continued for a period of 48 hours whereupon the mycelium and beer were extracted thoroughly with methylene chloride. The extract was washed with sodium bicarbonate solution and then with water, dried and concentrated in vacuo to give a-fiuoro- 1 1B, 170:, 2l-trihydroxy loa-methyl-l ,4-pregnadiene-3,20- dione.

Following the procedure of preparation 12, but substituting as starting material a-fluoro-llfl, 17a, 2l-trihydroxy-l6amethyl-4-pregnene-3,20-dione there was likewise produced 6a-fluoro-l lB, 17a, 2 l -trihydroxyl 6a-methyll ,4- pregnadiene-3,20-dione.

2 l-trihydroxyl a-methyll ,4-

The compound has a melting point of 224-227 centigrade and the analysis below Calculated for C,,H,,,O F: F, 4.84.

Found: F, 5.50.

PREPARATION l3 6a-fluoro-l 1,8, 2 l -trihydroxyl 6a-methyll ,4- pregnadiene-3,20-dione 2 l -acetate 1.5 grams of 6a-fluoro-l 113, Hot, 2l-trihydroxy-l6amethyl-l,4-pregnadiene-3,20-dione was dissolved in 20 milliliters of pyridine and I5 milliliters of acetic anhydride and the mixture heated at 40 centigrade for 4 hours. The solution was cooled and then slowly diluted with water. The precipitated steroid was removed by filtration, washed with water and dried to give a-fluoro-l 13, 17a, 2l-trihydroxyl6a-methyll ,4-pregnadiene-3,ZO-dione 2 l -acetate.

The compound was found to melt at l78l8 l centigrade and then resolidifies and again melted at 236-238 centigrade. Further it was found that A 242 mu (El4,700), [01],,

max.

91 (acetone), and the analysis below pregnadiene-3,20-dione is converted to other 2l-esters by reaction with the appropriate acid anhydride, acid chloride, or bromide or by other methods known in the art, e.g., by ester exchange, acid in the presence of an esterification catalyst, etc., to produce fia-fluoro-l 1B, 170:, 2l-trihydroxy-l6amethyl- 1 ,4-pregnadiene-3,20-dione 2 l-acylates which include those wherein the acyl radical of the 2l-acylate group is the acyl radical of, for example a lower aliphatic acid, e.g., formic, propionic, butyric, isobutyric, valeric, isovaleric, trimethylacetic, 2-methylbutyric, 3-ethylbutyric, hexanoic, diethylacetic, triethylacetic, heptanoic, octanoic, aethylisovaleric, a cyclic acid, e.g., cyclopropylideneacetic, a cycloaliphatic acid, e.g., cyclopentylformic, cyclopentylacetic B-cyclopentylpropionic, cyclohexylformic, cyclohexylacetic, B-cyclohexylpripionic, an aryl or alkaryl acid, e.g., benzoic 2,

3, or 4-methylbenzoic, 2,3-, 2,4-, 2,5-, 2,6-, 3,4- and 3,5-'

dimethylbenzoic, ethylbenzoic, 2,4,6-trimethylbenzoic, 2,46- triethylbenzoic, a-naphthoic, 3-methyl-a-naphthoic, an aralkyl acid, e.g., phenylacetic, phenylpropionic, diphenylacetic, triphenylacetic, a dibasic acid, (which can be converted to water soluble, e.g., sodium salts), e.g., succinic, glutaric, amethylglutaric, ,B-methylglutaric, Bfi-dimethylglutaric, adipic, pimelic, suberic, a hydroxy acid, e.g., glycolic, lactic, citric, tartaric, d-maleic, d-glyceric, mannonic, gluconic, salicycli, 2,3,4-trimethoxybenzoic, a-naphthoxyacetic, or other acyl acid.

PREPARATION l4 6a-fluoro-l 18, 17a, 2 l -trihydroxyl 6a-methyll ,4- pregnadiene-3 ,20-dione-2 l -hemisuccinate.

A solution is prepared by stirring 25 grams of succinic anhydride in 250 milliliters of pyridine. With continued stirring 25 grams of 6a-fluoro-1IB, 17a, 2l-trihydroxy-l6a-methyll,4-pregnadiene-3,20-dione (powdered) is added gradually over a period of 2-3 minutes. The stirring is continued until the steroid is dissolved and the reaction mixture allowed to stand at room temperature for 20 hours. The reaction mixture is then gradually (over a period of 5 minutes) poured, with stirring, into a cold hydrochloric acid solution prepared by vigorously stirring 300 milliliters of concentrated hydrochloric acid into 1,250 grams of ice in 1 liter of water. The stirring is then continued for 30 minutes. The reaction mixture is then filtered and the cake washed with water (about 500 milliliters) until the filtrate has a pH of 4 or higher and dried under vacuum at 50-60 centigrade. Following the above procedure 6a-fluorol ,8, I701, 2 l -trihydroxyl 6o1-methyll ,4-

pregnadiene-3,20-dione 2 l -hemisuccinate is obtained.

The above product is purified by dissolving it in 125 milliliters of acetone at 50 centigrade. The solution is treated with 2.5 grams of decolorizing carbon, filtered, and the cake washed with 25 milliliters of acetone. The filtrate and washings are reheated to 50 centigrade and diluted with l20 milliliters of water, seeded with 6a-fluoro-l 1B, 17a, 21- trihydroxy-l 6a-methyll ,4-pregnadiene-3,20-dione 2 l -hemisuccinate, stirred for 30 minutes, and allowed to crystallize at room temperature for 16 hours. The crystals are filtered off, washed l with [5 milliliters of acetone and (2) with 20 milliliters of water, and dried under vacuum at 50-60 centigrade.

PREPARATION 15 Sodium 6afluoro-l 1,8, 17112l-trihydroxy-l6a-methyl-l ,4 pregnadiene-3,20-dione 2 l -hemisuccinate A solution is prepared by warming 400 grams of 6a-fluoro- 1 15, 17a, 2 l -trihydroxyl 6a-methyll ,4-pregnadiene-3 ,20- dione 21-hemisuccinate in 1.5 liters of acetone and cooling to room temperature. With stirring, 1,600 milliliters of 0.5 normal aqueous sodium hydroxide is gradually added over a period of minutes. The pH is not allowed to rise above about pH 7.5. The end point adjustment is made by adding 10 milliliter portions of 0.5 N aqueous sodium hydroxide until a 10 milliliter test portion, when diluted with 10 milliliters of water, had a pH of 7.2 to 7.4. About 80 milliliters is required. The reaction mixture is then concentrated to about 2 liters in an atmosphere of nitrogen and under vacuum. The pot temperature should not exceed about 26 centigrade. The concentrate is treated with grams of diatomaceous earth, filter sterilized and lyophilized. Following this procedure the sodium salt of a-fluoro-l 1B, 1711, 2l-trihydroxy-l6a-methyl-l,4- pregnadiene-3,20-dione 2 l-hemisuccinate is obtained.

The compositions of the present invention are preferably presented for administration in unit dosage forms such as tablets, capsules, powders, granules, sterile parenteral solutions or suspensions, oral solutions or suspensions, topical ointments, creams, lotions and the like.

For oral administration either solid or fluid unit dosage forms can be prepared. For preparing solid compositions such as tablets, the principal active ingredient is mixed with conventional ingredients such as talc, magnesium stearate, dicalcium phosphate, magnesium aluminum silicate, starch, lactose, acacia, and functionally similar materials as pharmaceutical diluents or carriers. The tablets can be laminated or otherwise compounded to provide a dosage form affording the advantage of prolonged or delayed action or predetermined successive action of the enclosed medication. For example, the tablet can comprise an inner dosage and an outer dosage component, the latter being in the form of an envelope over the former. The two components can be separated by an enteric layer which serves to resist disintegration in the stomach and permits the inner component to pass intact into the duodenum or to be delayed in release. A variety of materials can be used for such enteric layers or coatings, such materials including a number of polymeric acids or mixture of polymeric acids with such materials as shellac, cetyl alcohol, cellulose acetate and the like. Alternatively, the two component system can be utilized for preparing tablets containing two or more incompatible active ingredients. Capsules, like tablets, are prepared by mixing the steroid with an inert pharmaceutical diluent and filling the mixture into a hard gelatin capsule of appropriate size. Soft gelatin capsules are prepared by machine encapsulation of preparing a slurry of the steroid with light liquid petrolatum or other inert oil.

Fluid unit dosage forms for oral administration such as syrups, elixirs, and suspensions can be prepared. The watersoluble forms can be dissolved in an aqueous vehicle together with sugar, flavoring agents and preservatives to form a syrup. An elixir is prepared by using a hydroalcoholic (ethanol) vehicle with suitable sweeteners such as sugar, saccharin, and cyclamate together with a flavoring agent. Suspensions can be prepared of the insoluble forms with a syrup vehicle with the aid of a suspending agent such as acacia, tragacanth, methylcellulose and the like.

Topical ointments can be prepared by dispersing the steroid in a suitable ointment base such as petrolatum, lanolin, polyethylene glycols, mixtures thereof, and the like. Advantageously the steroid is finely divided by means of a colloid mill utilizing light liquid petrolatum as a levigating agent. Creams and lotions are similarly prepared by dispersing the steroid in the oil phase of the system.

For parenteral administration, fluid unit dosage forms are prepared utilizing the steroid and a sterile vehicle, water being preferred. The steroid, depending on the form and concentration used, can be either suspended or dissolved in the vehicle. In preparing solutions the water-soluble steroid can be dissolved in water for injection and filter sterilized before filling into a suitable vial or ampul and sealing. Advantageously adjuvants such as a local anesthetic, preservative and buffering agents can be dissolved in the vehicle. To enhance the stability, the composition can be frozen after filling into the vial and the water removed under vacuum: the dry lyophilized powder is then sealed in the vial and an accompanying vial of water for injection is supplied to reconstitute the powder prior to use. Parenteral suspensions are prepared in substantially the same manner except that the steroid is suspended in the vehicle instead of being dissolved and sterilization cannot be accomplished by pharmaceutical The steroid can be sterilized by exposure to ethylene oxide before suspending in the invention are vehicle. Advantageously, a surfactant or wetting agent is included in the composition to facilitate uniform distribution of the steroid.

The term unit dosage form as used in the specification and claims refers to physically discrete units suitable as unitary dosages for human subjects and animals, each unit containing a predetermined quantity of active material calculated to produce the desired therapeutic effect in association with the required pharmaceutical diluent, carrier or vehicle. The specifications for the novel unit dosage forms of this invention are dictated by and directly dependent on (a) the unique characteristics of the active material and the particular therapeutic effect to be achieved, and (b) the limitations inherent in the art of compounding such an active material for therapeutic use in humans and animals, as disclosed in detail in this specification, these being features of the present invention. Examples of suitable unit dosage forms in accord with this invention are tablets, capsules, pills, powder packets, granules, wafers, cachets, teaspoonfuls, tablespoonfuls, dropperfuls ampuls vials, segregated multiples of any of the foregoing, and other forms as herein described.

In addition to the administration of fia-fluoro-l 1B, 21- trihydroxyl 6a-methyl-l ,4-pregnadiene-3,20-dione as the principal active ingredient of compositions for the treatment of the conditions described herein, the said compound of the novel compositions can be included with other types of compounds to obtain advantageous combinations of properties. Such combinations include 6a-fluoro-l 1B, l7a, Zl-trihydroxy-l6a-methyl-l,4-pregnadiene3,20-dione with antibiotics such as chloramphenical, penicillin, tetracyclines, erythromycin, novobiocin, neomycin, polymyxin, and bacitracin; analgesics such as aspirin, sodium salicylate, N-acetyl-paminophenol and salicylarnide; agents which lessen pain by means of altering the subjects attitude such as the amphetamines and tranquilizers; local anesthetics such as benzocaine, procaine, and tetracaine; antacids such as calciurn carbonate, aluminum hydroxide, basic aluminum carbonate, and bismuth subcarbonate', and the vitamins, especially ascorbic acid and the Vitamin B-complex.

The dosage of the 6afluoroll 1B, 1170:, 2l-trihydroxy-l 6amethyl-l,4-pregnadiene-3,20-dione for treatment depends on route of administration, age, weight, and condition of the patient. A dosage schedule of from about 0.1 to about 10 milligrams, one to four times daily, embraces the effective range for the treatment of most conditions for which the compounds are effective. The 6a-fluoro-l la, 17a, 2l-trihydroxy-l6acontaining 0.75

methyl-l ,4-pregnadiene-3,20-diones are compounded with suitable pharmaceutical carriers for convenient and effective administration. In the preferred embodiment of this invention the dosage units contain the steroid in 0.1, 0.25, 0.50, 0.75, l, and 10 milligram amounts for systemic treatment and in 0.0 l 0.05, 0.1, l and percent amounts for topical or localized treatment. The dosage of compositions containing the steroid and one or more other active ingredients is to be determined with reference to the usual dosage of each such ingredient.

The following examples are illustrative of the best mode contemplated by the inventors for carrying out their invention and are not to be construed as limiting.

EXAMPLE 1 Ten thousand tablets, each containing l0 milligrams of 6afluoro-l6a-methylprednisolone, are prepared from the following types and amounts of ingredients:

a-fluorol oat-methylprednisolone [00 gm. Lactose 1,000 grn Starch paste (l0% w./v.' starch in water) 100 gm. Starch 32.5 gm. Calcium stearate 6.5 gm.

The steroid and lactose are mixed together until the steroid is uniformly dispersed and then a granulation prepared by the addition of the starch paste. The granules are dried at l20 F. for 20 hours and the dried granules forced through a No. 16 screen. The granules are lubricated by the addition of the starch and calcium stearate and compressed into tablets each tablet containing milligrams of steroid.

The tablets so prepared are useful in the treatment of rheumatoid arthritis by the oral administration of 1 tablet three times a day.

Following the procedure of the preceding example, tablets containing 1 and 0.1 milligram of 6a-fluoro-l6a-methylprednisolone are prepared by reducing the amount of 6afluoro-lfizz-methylprednisolone from 100 grams to 10 grams and 1 gram respectively.

EXAMPLE 2 Ten thousand tablets, each containing 0.5 milligrams of 6afluoro-l6a-methylprednisolone and 325 milligrams (5 grains) of acetylsalicylic acid as therapeutic ingredients, are prepared from the following types and amounts of ingredients:

6u-fluoro-l6a-methylprednisolone 5 gm. Acetylsalicylic acid 3.250 gm. Starch 200 gm. Magnesium stearate 50 gm.

The steroid, aspirin, and starch are mixed together until uniformly dispersed. The mixture is then slugged and the slugs broken into granules. The magnesium stearate is added to the granules and the mixture compressed into tablets.

The tablets so prepared are useful in the treatment of rheumatoid arthritis by the oral administration of one tablet three times a day.

Following the procedure of the preceding example, tablets containing 0.25 milligrams of 6a-fluoro-l6a-methylprednisolone in addition to the 5 grains of aspirin are prepared by reducing the amount of 6a-fluoro-l6a-methylprednisolone from 5 grams to 2.5 grams.

EXAMPLE 3 One thousand two-piece hard gelatin capsules, each capsule milligrams of 6a-fluoro-l6a-methylprednisolone, are prepared from the following types and amounts of ingredients:

tm-l'luoro-Mar-methylprednisolone 0.75 gm. Corn starch I50 gm. Magnesium stearate 25 gm. Hard gelatin capsules L000 EXAMPLE 4 One thousand grams of a topical ointment for application to the eye or car containing 0.1 percent of 6a-fluoro-l6amethylprednisolone and 0.6 percent neomycin sulfate are prepared from the following types and amounts of ingredients:

a-fluoro-lwmethylprednisolone (micronized) l gm. Neomycin sulfate (micronized) 6 gm. Light liquid petrolatum 250 gm. Wool fat 200 gm. White petrolatum q.s. ad. L000 gm.

The wool fat, white petrolatum and 200 grams of light liquid petrolatum are melted together and held at [10 F. The steroid and neomycin are mixed with the remaining light liquid petrolatum and passed through a colloid mill. After passing through the mill, the mixture is stirred into the melt. With continued stirring, the melt is allowed to cool until congealed.

The foregoing ointment is usefully applied to the eye and ear for local treatment of infection and inflammation.

Following the procedure of the preceding example. an ointment containing 0.0l percent of a 6a-fluoro-l6a-methylprednisolone is prepared by decreasing the amount of steroid from 1 gram to 0.l gram. Similarly the 6a-fluoro46a-methylprednisolone 2l-acetate can be substituted for the free alcohol forms of the example.

EXAMPLE 5 One thousand grams of a topical ointment containing 0.1 percent of a-fluoro-l(Sat-methylprednisolone is prepared from the following types and amounts of ingredients:

ba-fluoro-loot-methylprednisolone (Micronized) 1 gm. Light liquid petrolatum I00 gm. Wool fat 200 gm. White petrolatum q.s. ad. 1.000 gm.

The wool fat, white petrolatum and one-half of the light liquid petrolatum are melted together and held at a temperature of l60 F. The steroid is added to the remaining light liquid petrolatum and passed through a colloid mill. After passing through the mill, the steroid is stirred into the melt. With continued stirring, the melt is allowed to cool until congealed.

The foregoing ointment is usefully applied to the skin for the treatment of allergic dermatoses and other inflammatory skin diseases.

Following the procedure of the preceding example, an ointment containing 5 percent of 6a-fluoro-l6a-methylprednisolone is prepared by increasing the amount of steroid from 1 gram to 50 grams. Similarly the oa-fluoro-la-methylprednisolone 2l-acetate can be substituted for the free alcohol form of the example.

EXAMPLE 6 One thousand cc. of a sterile solution for parenteral administration containing l mg./cc. of 6a-fluoro-l6a-methylprednisolone 2l-succinate sodium is prepared from the following types and amounts of ingredients:

fia fluoro-loot-methylprednisolone 2lsuccinate sodium I gm. Sodium biphosphate, anhydrous 0.8 gm. Sodium phosphate, exsiccated 0.87 gm. Lactose 50 gm.

Water for injection L000 cc.

The ingredients are dissolved in the water and the solutionsterilized by filtration. The sterile solution is aseptically filled into sterile vials, l cc./vial, and frozen. The water is removed under high vacuum and the vials containing the lyophilized powder are sealed. Just prior to use, sufficient water for in jection to make 1 cc. of solution is added to the vial.

The parenteral solution so prepared is useful in the treatment of rheumatic fever whenadministered parenterally (intramuscularly or intravenously) at a dose of 1 cc.

Following the procedure of the preceding example, a parenteral solution containing 0.1 or 10 milligrams of 6afluoro-lfia-methylprednisolone 2l-succinate sodium is prepared by substituting the amount of steroid from 1 gram to 0.1 gram and 10 grams respectively.

EXAMPLE 7 One thousand cc. of a solution for ophthalmic treatment containing 0.075 percent fiat-fluoro-16a-methylprednisolone 2l-succinate sodium and 6,000 units/cc. of polymyxin B sulfate are prepared from the following types and amounts of ingredients:

21-succinate sodium 0.75 gm. Polymyxin B sulfate (10.000 units/mg.) .6 gm. Sodium citrate 4.5 gm. Polyethylene glycol 4000 120 gm.

Polyvinylpyrrolidone l Sodium hydroxide q.s. pH 7 to 7.4 gm. Water for injection 1,000 cc.

The ingredients are dissolved in the water and the pH adjusted to from pH 7 to pH 7.4 by the addition of sodium hydroxide. The solution is sterilized by filtration and aseptically filled into sterile 5 cc. dropper bottles.

The compositions so prepared is useful for the treatment of infection and inflammation in the eye by the administration to the eye of one to five drops three times a day.

What is claimed is:

l. A therapeutic composition which comprises: as the principal active ingredient, a compound selected from the group consisting of (1) 6a-fluoro-1 1 B,l7a,21-trihydroxy-l6amethyl-1 ,4-pregnadiene-3,20-dione, (2) fia-fluoro-l 1,8, 160! .21-trihydroxy'16a-methyl-1,4-pregnadiene-3,20-dione 2 lacylates in which the acyl radical is that of an organic carboxylic acid containing one through 16 carbon atoms, and (3) salts of the 21-acylates of fia-fluoro-l1/3,17a,21-trihydroxyla-methyl-I,4-pregnadiene-3,20-dione, in combination with a pharmaceutical carrier.

2. A therapeutic composition comprising, in unit dosage form, at least about 0.1 milligram of a member selected from the group consisting of (1 6a-fluoro-1 l,B,l7a,2l-trihydroxy- 16a-methyl-1,4-pregnadiene-3,ZO-dione, (2) 6a-fluoro-l l [3,1704,2l-trihydroxy-l6a-methyl-l,4-pregnadiene-3,20-dione 2l-acy1ates in which the acyl radical is that of an organic carboxylic acid containing one through 16 carbon atoms, and 3) salts of the 2l-acylates of 6afluor0-l 1B,17a,21-trihydroxyl6a-methy| l ,4-pregnadiene3,20-dione, in combination with a'pharmaceutical carrier.

3. A therapeutic composition comprising, in unit dosage form, from about 0.1 to about milligrams of a member selected from the group consisting of 1) 6a-fluoro-11B,17a ,2l-trihydroxy-l6a-methyl-1,4-pregnadiene-3,20-dione, 2) 60z-flu0r0-l 113,17a,21-trihydroxy-l6a-methyl-1,4-

pregnadiene-3,20-dione 2l-acylates in which the acyl radical is that ofan organic carboxylic acid containing one through 16 carbon atoms, and (3) salts of the 2 l-acylates of 6a-fluor0-l 1 3,1 701,2 l-trihydroxyl6a-methyl-1 ,4-pregnadiene-3,20- dione, as an essential active ingredient in combination with a pharmaceutical carrier.

4. A therapeutic composition comprising from about 0.01 percent to about 5 percent of a member selected from the group consisting of l fia-fluoro-l 13,17a,21'trihydroxy-16amethyl-l,4pregnadiene-3,ZO-dione, (2) 6a-fluoro-l 113,170: ,21-trihydroxy-16a-methyl-l,4-pregnadiene-3,20-dione 21- acylates in which the acyl radical is that of an organic carboxylic acid containing one through 16 carbon atoms, and (3) salts of the 2l-acylates of 6a-fluoro-l l,B,l7a,2l-trihydroxylGa-methyll ,4-pregnadiene-3,20-dione, as an essential active ingredient in combination with a fluid pharmaceutical vehicle.

5. A therapeutic composition in tablet form comprising from about 0.1 to about 10 milligrams of a member selected from the group consisting of (1) fia-fluoro-l 1B,l7a,21- trihydroxy-16a-methyl-1,4-pregnadiene-3,20-dione (2) 6afluoro-l 1B,17a,21-trihydroxy-l6a-methyl-l,4-pregnadiene- 3,20-dione 21-acylates in which the acyl radical is that of an organic carboxylic acid containing one through 16 carbon atoms, and (3) salts of the 2l-acylates of 6a-fluoro-l 13,170: ,2 1 -trihydr0xyl a-methyll ,4-pregnadiene-3 ,20-dione, as an essential active ingredient in combination with a pharmaceuti cal diluent.

6. A sterile injectable composition for parenteral administration comprising at least about 0.011 percent of a member selected from the group consisting of (1) u-fluoro-l 1B,17a ,2l-trihydroxy-loa-methyl-1,4-pregnadiene-3,20-dione, (2) 6a-fluoro-1 1,8,1701,21-trihydroxy-16a-methyl-1 ,4- pregnadiene-3,20-dione 2l-acylates in which the acyl radical is that of an organic carboxylic acid containing one through 16 carbon atoms, and 3) salts of the 2l-acylates of 6a-fluoro-1 l 3,17a,2l-trihydroxy-lfia-methyl-1,4-prednadiene-3,20- dione, as an essential active ingredient in combination with a sterile vehicle.

7. A process for treating human and animal inflammatory conditions which comprises: administering a therapeutic composition containing a therapeutic amount of a compound selected from the group consisting of 1) oa-fluoro-l 1,8,1701 ,21-trihydroxy-16a-methyll ,4-pregnadiene-3,20-dione, (2 6a-fluoro-1 1 B, 1 711,2 1 -trihydroxyl a-methyl-l ,4- pregnadiene-3,20-dione 21-acylates in which the acyl radical is that of an organic carboxylic acid containing one through 16 carbon atoms, and (3) salts of the 2l-acylates of oa-fluoro-l l [3, :,2 l-trihydroxy-16a-methyl-l ,4-pregnadiene-3,20- dione, in combination with a pharmaceutical carrier.

8. A process for treating human and animal inflammatory conditions which comprises: administering a therapeutic composition containing from about 0.1 to about 10 milligrams per dosage unit of a compound selected from the group consisting of (l 6a-fluoro-l 1B,17a,21-trihydroxy-l 6a-methyl-l,4- pregnadiene-3,20-dione, (2) a fluoro-l 1/3,17a,21-trihydroxy-l fia-methyll ,4-pregnadiene-3 ,20-dione 2 l -acylates in which the acyl radical is that of an organic carboxylic acid containing one through 16 carbon atoms, and (3) salts of the 21-acylates of 6a-fluoro-11B,1701,2l-trihydroxy-la-methyl- 1,4-pregnadiene-3,20-dione, in combination with a pharmaceutical carrier. 

2. A therapeutic composition comprising, in unit dosage form, at least about 0.1 milligram of a member selected from the group consisting of (1) 6 Alpha -fluoro-11 Beta ,17 Alpha ,21-trihydroxy-16 Alpha -methyl-1,4-pregnadiene-3,20-dione, (2) 6 Alpha -fluoro-11 Beta ,17 Alpha ,21-trihydroxy-16 Alpha -methyl-1,4-pregnadiene-3,20-dione 21-acylates in which the acyl radical is that of an organic carboxylic acid containing one through 16 carbon atoms, and (3) salts of the 21-acylates of 6 Alpha -fluoro-11 Beta ,17 Alpha ,21-trihydroxy-16 Alpha -methyl-1,4-pregnadiene-3,20-dione, in combination with a pharmaceutical carrier.
 3. A therapeutic composition comprising, in unit dosage form, from about 0.1 to about 10 milligrams of a member selected from the group consisting of (1) 6 Alpha -fluoro-11 Beta ,17 Alpha , 21-trihydroxy-16 Alpha -methyl-1,4-pregnadiene-3,20-dione, (2) 6 Alpha -fluoro-11 Beta ,17 Alpha ,21-trihydroxy-16 Alpha -methyl-1,4-pregnadiene-3,20-dione 21-acylates in which the acyl radical is that of an organic carboxYlic acid containing one through 16 carbon atoms, and (3) salts of the 21-acylates of 6 Alpha -fluoro-11 Beta ,17 Alpha ,21-trihydroxy-16 Alpha -methyl-1,4-pregnadiene-3,20-dione, as an essential active ingredient in combination with a pharmaceutical carrier.
 4. A therapeutic composition comprising from about 0.01 percent to about 5 percent of a member selected from the group consisting of (1) 6 Alpha -fluoro-11 Beta ,17 Alpha ,21-trihydroxy-16 Alpha -methyl-1,4-pregnadiene-3,20-dione, (2) 6 Alpha -fluoro-11 Beta , 17 Alpha ,21-trihydroxy-16 Alpha -methyl-1,4-pregnadiene-3,20-dione 21-acylates in which the acyl radical is that of an organic carboxylic acid containing one through 16 carbon atoms, and (3) salts of the 21-acylates of 6 Alpha -fluoro-11 Beta ,17 Alpha , 21-trihydroxy-16 Alpha -methyl-1,4-pregnadiene-3,20-dione, as an essential active ingredient in combination with a fluid pharmaceutical vehicle.
 5. A therapeutic composition in tablet form comprising from about 0.1 to about 10 milligrams of a member selected from the group consisting of (1) 6 Alpha -fluoro-11 Beta ,17 Alpha ,21-trihydroxy-16 Alpha -methyl-1,4-pregnadiene-3,20-dione, (2) 6 Alpha -fluoro-11 Beta ,17 Alpha ,21-trihydroxy-16 Alpha -methyl-1,4-pregnadiene-3,20-dione 21-acylates in which the acyl radical is that of an organic carboxylic acid containing one through 16 carbon atoms, and (3) salts of the 21-acylates of 6 Alpha -fluoro-11 Beta ,17 Alpha ,21-trihydroxy-16 Alpha -methyl-1,4-pregnadiene-3,20-dione, as an essential active ingredient in combination with a pharmaceutical diluent.
 6. A sterile injectable composition for parenteral administration comprising at least about 0.01 percent of a member selected from the group consisting of (1) 6 Alpha -fluoro-11 Beta ,17 Alpha ,21-trihydroxy-16 Alpha -methyl-1,4-pregnadiene-3,20-dione, (2) 6 Alpha -fluoro-11 Beta ,17 Alpha ,21-trihydroxy-16 Alpha -methyl-1,4-pregnadiene-3,20-dione 21-acylates in which the acyl radical is that of an organic carboxylic acid containing one through 16 carbon atoms, and (3) salts of the 21-acylates of 6 Alpha -fluoro-11 Beta ,17 Alpha ,21-trihydroxy-16 Alpha -methyl-1,4-prednadiene-3,20-dione, as an essential active ingredient in combination with a sterile vehicle.
 7. A process for treating human and animal inflammatory conditions which comprises: administering a therapeutic composition containing a therapeutic amount of a compound selected from the group consisting of (1) 6 Alpha -fluoro-11 Beta ,17 Alpha ,21-trihydroxy-16 Alpha -methyl-1,4-pregnadiene-3,20-dione, (2) 6 Alpha -fluoro-11 Beta ,17 Alpha ,21-trihydroxy-16 Alpha -methyl-1,4-pregnadiene-3,20-dione 21-acylates in which the acyl radical is that of an organic carboxylic acid containing one through 16 carbon atoms, and (3) salts of the 21-acylates of 6 Alpha -fluoro-11 Beta ,17 Alpha ,21-trihydroxy-16 Alpha -methyl-1,4-pregnadiene-3,20-dione, in combination with a pharmaceutical carrier.
 8. A process for treating human and animal inflammatory conditions which comprises: administering a therapeutic composition containing from about 0.1 to about 10 milligrams per dosage unit of a compound selected from the group consisting of (1) 6 Alpha -fluoro-11 Beta ,17 Alpha ,21-trihydroxy-16 Alpha -methyl-1,4-pregnadiene-3,20-dione, (2) 6 Alpha -fluoro-11 Beta , 17 Alpha ,21-trihydroxy-16 Alpha -meThyl-1,4-pregnadiene-3,20-dione 21-acylates in which the acyl radical is that of an organic carboxylic acid containing one through 16 carbon atoms, and (3) salts of the 21-acylates of 6 Alpha -fluoro-11 Beta ,17 Alpha , 21-trihydroxy-16 Alpha -methyl-1,4-pregnadiene-3,20-dione, in combination with a pharmaceutical carrier. 